KR20070029680A - Display and method for driving same - Google Patents

Abstract

A display comprises a self-luminous display element (10) which transmits a light when it displays no image and a display element (40) which is formed on the display element (10) and capable of switching between a light-transmitting state and an opaque state. The display displays a certain image by superimposing an image displayed by the display element (10) on another image displayed by the display element (40). With a display having such a structure, a good black display can be attained even when the outside light is bright. A full color display with good contrast can be also realized by such a display. Furthermore, by having a black display on the entire display element (40), the information on the display screen of the display element (10) is not seen through the display screen of the display element (40). Consequently, it is possible to protect privacy and security of the displayed information. ® KIPO & WIPO 2007

Description

Display device and driving method thereof {DISPLAY AND METHOD FOR DRIVING SAME}

Field of technology

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device and a driving method thereof, and more particularly, to a self-luminous display device and a driving method thereof that can be used in a glass window, a face-to-face display, and the like.

Background

Recently, a display device (transparent display device) that becomes transparent in an image non-display state has been attracting attention as a display device that can be used for a glass window or a face-to-face display. As such a display apparatus, what used the liquid crystal element and the self-luminous electro luminescence (EL) element is proposed.

In particular, since the EL element has good transparency and display characteristics, application to a transparent display device is expected. In addition, the transparent display apparatus using an EL element is described in Unexamined-Japanese-Patent No. 11-339953, for example.

However, good black display is difficult in the conventional self-luminous transparent display device. Usually, when black is displayed in a self-luminous display device, a method of not emitting light (non-emission) is used. However, in the transparent display device, since the non-light emitting area is in a light transmitting state, black display is difficult, particularly in a place where the influence of the external environment such as external light is strong. Therefore, in the conventional self-luminous transparent display device, black display was not good and full color was difficult.

SUMMARY OF THE INVENTION An object of the present invention is to provide a display device and a driving method thereof capable of good black display and high contrast with good contrast even when the influence of external environment such as external light is strong.

Disclosure of the Invention

According to one aspect of the present invention, a self-luminous first display element that is in a light transmissive state when the image is not displayed, and an agent that is formed on the first display element and that can switch a light transmissive state and a light impermeable state. Provided is a display device having two display elements and displaying a predetermined image by superimposing an image displayed by the first display element and an image displayed by the second display element.

According to another aspect of the present invention, when the image is not displayed, the self-luminous first display element which is in a light transmissive state and the first display element are formed, and the light transmissive state and the light impermeable state can be switched. A method of driving a display device having a second display element, the method of driving a display device displaying a predetermined image by superimposing an image displayed by the first display element and an image displayed by the second display element. This is provided.

According to still another aspect of the present invention, when the image is not displayed, the self-luminous first display element which is in a light transmissive state and the first display element are formed so as to switch between the light transmissive state and the light impermeable state. A method of driving a display device having a second display element which can be formed on the second display element and which is formed on the second display element and which is in a light transmissive state when no image is displayed. By superimposing the image displayed by the image displayed by the said 2nd display element, the 1st predetermined image is displayed, the image displayed by the said 3rd display element, and the image displayed by the said 2nd display element By superimposing images, a driving method of a display device for displaying a second predetermined image is provided.

Brief description of the drawings

1 is a schematic cross-sectional view showing the structure of a display device according to a first embodiment of the present invention.

2 is a diagram showing a first driving method of the display device according to the first embodiment of the present invention.

3 is a view showing a second driving method of the display device according to the first embodiment of the present invention.

4 is a schematic cross-sectional view showing the structure of a display device according to a second embodiment of the present invention.

5 is a schematic cross-sectional view showing the structure of a display device according to a third embodiment of the present invention.

6 is a schematic cross-sectional view showing the structure of a display device according to a fourth embodiment of the present invention.

7 is a view showing the operation of the electrophoretic display.

8 is a schematic cross-sectional view showing the structure of a display device according to a fifth embodiment of the present invention.

9 is a schematic cross-sectional view showing the structure of a display device according to a sixth embodiment of the present invention.

To practice the invention  Best form for

[First embodiment]

A transparent display device according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 3. 1 is a schematic sectional view showing a structure of a display device according to the present embodiment, and FIGS. 2 and 3 are diagrams showing a driving method of the display device according to the present embodiment.

First, the structure of the display device which concerns on this embodiment is demonstrated using FIG.

The display device according to the present embodiment is a transparent display device capable of black display, which is configured by combining a self-luminous transparent display element and a transparent display element capable of black display (light-transmissive state). The transparent organic EL display 10 is used as a self-luminous transparent display element, and the transparent liquid crystal display 40 is used as a transparent display element which can display black. As shown in FIG. 1, the organic electroluminescent display 10 and the liquid crystal display 40 overlap each other so that the position of the pixel of each display element may be aligned, and is adhered by the epoxy resin adhesive 60, for example.

The organic EL display 10 is formed on a transparent substrate 12 made of a transparent material such as glass, quartz, resin, or the like. On the transparent substrate 12, the transparent electrode 14 which consists of a transparent material, for example, ITO with a film thickness of 150 nm is formed. The transparent electrodes 14 are formed individually corresponding to the pixel areas.

On the transparent electrode 14, the light emitting layer 16 which consists of organic electroluminescent material is formed. The light emitting layer 16 includes a hole injection layer 18 formed on the transparent electrode 14, a hole transport layer 20 formed on the hole injection layer 18, and a light emitting layer 22 formed on the hole transport layer 20. And the electron transport layer 24 formed on the light emitting layer 22.

The hole injection layer 18 is made of, for example, 2TNATA having a thickness of 200 nm. The hole transport layer 20 is made of, for example, α-NPD having a thickness of 20 nm. The electron transport layer 24 is made of Alq having a film thickness of 20 nm, for example.

The light emitting layer 22 is comprised by any one of the red light emitting layer 22R, the green light emitting layer 22G, and the blue light emitting layer 22B for every pixel. The red emitter layer 22R is made of Alq doped with DCM 1% having a film thickness of 30 nm, for example. The green light emitting layer 22 is made of TYG-201 having a thickness of 30 nm, for example. The blue light emitting layer 22B is made of, for example, a CBP doped with BAlq having a thickness of 20 nm of 5%, and a laminated film of BCP having a thickness of 10 nm, for example.

On the light emitting layer 16, the back electrode 26 which consists of transparent electrode materials, such as ITO, and translucent electrode materials, such as Li, Mg, Al, is formed. The back electrode 26 is composed of, for example, a laminated film of an MgAg film having a film thickness of 15 nm and an ITO film having a film thickness of 150 nm, for example. In addition, the back electrode 26 is an electrode common to each pixel part.

On the transparent substrate 12 in which the transparent electrode 14, the light emitting layer 16, and the back electrode 26 were formed, the sealing plate 28 which consists of glass is formed, for example. The sealing plate 28 is for protecting the light emitting layer 16 made of an organic EL material from external air such as oxygen or hydrogen. Between the transparent substrate 12 and the sealing plate 28, the transparent substrate 12 and the sealing plate 28 are adhere | attached with the epoxy resin adhesive 30 etc., for example in nitrogen atmosphere, and are sealed. In addition, at this time, the getter agent which collects water is put between the transparent substrate 12 and the sealing plate 28, and protection from external air is ensured. In other words, a transparent liquid getter agent is preferable.

The liquid crystal display 40 is formed in the pair of transparent substrates 42 and 44 made of transparent materials such as glass, quartz, resin, and the like, for example. On the opposing surfaces of each of the transparent substrates 42 and 44, transparent electrodes 46 and 48 made of transparent electrode materials such as ITO are formed, respectively. At least one of the transparent electrodes 46 and 48 is partitioned for each pixel, and a voltage can be applied to each pixel by wiring (not shown). Alignment films 50 and 52 are formed on the transparent electrodes 46 and 48, respectively. The alignment films 50 and 52 are for orienting liquid crystal molecules in a predetermined direction, and are formed by, for example, rubbing a polyimide film with nylon in a predetermined direction. The liquid crystal 54 (for example, Merck Japan make, MJ95785) is sealed between the alignment films 50 and 52.

The polarizing plates 56 and 58 are formed in the non-facing surface of the transparent substrates 42 and 44, respectively. The polarizing plates 56 and 58 are, for example, sandwiching a polarizing layer made of a polyvinyl alcohol-iodine system with a plastic film, and when no voltage is applied between the transparent electrodes 46 and 48 (when the power is OFF). Light is transmitted (transparent), and is disposed so as to be opaque (black display) when a voltage is applied between the transparent electrodes 46 and 48 (when the power supply is turned on).

Next, a driving method of the display device according to the present embodiment will be specifically described with reference to FIGS. 2 and 3. As a driving method of the display device which concerns on this embodiment, the following two methods can be considered, for example.

(Drive method 1)

In this driving method, the corresponding pixels of the organic EL display 10 and the liquid crystal display 40 are simultaneously driven. And as shown to FIG. 2A, the organic electroluminescent display 10 displays the color display part except the black part of a display image. On the other hand, the liquid crystal display 40 displays only the black part of a display image.

By using this driving method, the image displayed by the organic EL display 10 is superimposed on the image displayed by the liquid crystal display 40 on the display surface of the organic EL display 10 side, and the image as shown in FIG. 2B. Is displayed. Moreover, on the liquid crystal display 10 side display surface, the image displayed by the liquid crystal display 40 is superimposed on the image displayed by the organic electroluminescent display 10, and the image as shown in FIG. 2C is displayed.

As described above, the display device according to the present embodiment becomes a full color double-sided light emitting display device. However, when an image as shown in FIG. 2B is displayed on one display surface, for example, as shown in FIG. 2C, the other display surface is left and right with the image of the said one display surface. A symmetrical image is displayed.

(Drive method 2)

As shown to FIG. 3A, the organic electroluminescent display 10 displays the color display part except the black part of a display image. In the liquid crystal display 40, the whole image area | region is made into one surface black display. In this driving method, the display of the liquid crystal display 40 need not be performed simultaneously with the driving of the organic EL display 10.

By using this driving method, the image displayed by the organic EL display 10 is superimposed on the image displayed by the liquid crystal display 40 on the display surface of the organic EL display 10 side, and the image as shown in FIG. 3B. Is displayed. On the other hand, on the display surface of the liquid crystal display 10 side, since the image displayed by the organic EL display 10 is completely blocked by the image displayed by the liquid crystal display 40, an image as shown in FIG. 3C is displayed. .

Thus, in this driving method, a full color image is displayed on the display surface of the organic EL display 10 side (see FIG. 3B), but the display surface of the liquid crystal display 40 side becomes black display on one side and no image is displayed. (See FIG. 3C).

In other words, the present driving method can also be said to have an effect of preventing image information from being seen by a person on the display surface side of the liquid crystal display 40 side. That is, in the conventional transparent display device, since display information is displayed on both display surfaces of the display device, there was a problem in privacy and security. However, by using this driving method, display information is displayed only on one surface side of the display device. It doesn't work. Therefore, according to the display device which concerns on this embodiment, the privacy and security of display information can be protected.

As a result of manufacturing the display device according to the present embodiment and performing an operation test, it was possible to perform full-color display that was transparent during normal operation (when the power was turned off) and had good contrast during image display. Moreover, when the said drive method 1 was used, the image was confirmed on both display surfaces. Moreover, when the said drive method 2 was used, the liquid crystal display side display surface became black display, and the image was not able to be recognized.

As described above, according to the present embodiment, since the display device is configured by combining the self-luminous transparent display element and the transparent display element capable of black display, a good black display can be obtained even when the external light is strong, and the contrast is good in full color display. Can be carried out.

Moreover, by making the black display the transparent display element which can display black on one surface, the information of the self-luminous type transparent display element side display surface is not displayed on the transparent display element side display surface which can display black. Thus, privacy and security of the display information can be protected.

Second Embodiment

The display device and driving method thereof according to the second embodiment of the present invention will be described with reference to FIG. 4. In addition, the same code | symbol is attached | subjected to the display device which concerns on 1st Embodiment shown in FIGS. 1-3, and the same component as the drive method, and description is abbreviate | omitted or simplified.

4 is a schematic cross-sectional view showing the structure of the display device according to the present embodiment.

The display device according to the present embodiment is a transparent display device configured by combining a self-luminous transparent display element and a transparent display element capable of black display, similarly to the display device according to the first embodiment. As the transparent organic EL display 10, a transparent liquid crystal display 40 is used as a transparent display element capable of black display.

As shown in FIG. 4, the main feature of the display device according to the present embodiment is a sealing plate for sealing the light emitting layer 16 of the organic EL display 10 by the transparent substrate 42 of the liquid crystal display 40. It is in that it consists of.

When the organic EL display 10 and the liquid crystal display 40 are bonded together, in order to increase the transmittance of the entire display device, a substance having a refractive index equivalent to that of the sealing plate 28 and the transparent substrate 42 is interposed in the bonding portion. It is preferable to make it. In the case of the display device according to the first embodiment shown in FIG. 1, it is conceivable to interpose a material having such a refractive index between the sealing plate 28 and the transparent substrate 42.

On the other hand, in the display device which concerns on this embodiment, in order to acquire the effect equivalent to this or more, the sealing plate for sealing the light emitting layer 16 of the organic electroluminescent display 10 by the transparent substrate 42 of the liquid crystal display 40. It consists of: By constituting the display device in this manner, the change in the refractive index at the bonding portion between the organic EL display 10 and the liquid crystal display 40 is eliminated, and the transmittance of the entire display device can be greatly improved.

The above configuration has various merit as well as merit in display characteristics. For example, since the process of adhering the sealing plate 28 and the process of adhering the organic EL display 10 and the liquid crystal display 40 can be performed in one step, the manufacturing process is simplified and further the production. We can reduce cost. In addition, since the sealing plate 28 is unnecessary, the number of parts can be reduced, and the product cost can also be reduced. In addition, the display device can be made thinner by the sealing plate 28.

Thus, according to this embodiment, since the transparent substrate of a liquid crystal display is used as a sealing plate of an organic electroluminescent display, the loss of the transmitted light in the bonding part of the organic electroluminescent display 10 and the liquid crystal display 40 can be prevented. have. As a result, the transmittance of the entire display device can be significantly improved. In addition, since the number of manufacturing steps and the number of parts are reduced, the manufacturing cost and the product cost can be reduced.

[Third Embodiment]

The display device and driving method thereof according to the third embodiment of the present invention will be described with reference to FIG. 5. In addition, the same code | symbol is attached | subjected to the display apparatus which concerns on the 1st and 2nd embodiment shown in FIGS. 1-4, and its drive method, and the same code | symbol is abbreviate | omitted or simplified.

5 is a schematic cross-sectional view showing the structure of the display device according to the present embodiment.

First, the structure of the display device which concerns on this embodiment is demonstrated using FIG.

In the display device according to the first embodiment shown in FIG. 1, the display device according to the present embodiment is a transparent organic EL display as a self-emitting transparent display element on the transparent substrate 44 side of the liquid crystal display 40. It is characteristic that 70 is further bonded. That is, the organic electroluminescence display 10 and the organic electroluminescence display 70 are formed so that the liquid crystal display 40 may be interposed between them.

As shown in FIG. 5, the organic EL display 70 is superimposed so that the pixel positions of the organic EL display 10 and the liquid crystal display 40 are aligned, and is bonded by, for example, an epoxy resin adhesive 92. have.

The organic EL display 70 is formed on a transparent substrate 72 made of a transparent material such as glass, quartz, or resin. On the transparent substrate 72, a transparent electrode 74 made of a transparent material, for example, ITO having a thickness of 150 nm is formed. The transparent electrode 74 is formed separately corresponding to each pixel area.

On the transparent electrode 74, the light emitting layer 76 which consists of organic electroluminescent material is formed. The light emitting layer 76 includes a hole injection layer 78 formed on the transparent electrode 74, a hole transport layer 80 formed on the hole injection layer 78, and a light emitting layer 82 formed on the hole transport layer 80. And the electron transport layer 84 formed on the light emitting layer 82.

The hole injection layer 78 is made of, for example, 2TNATA having a thickness of 200 nm. The hole transport layer 80 is made of, for example, α-NPD having a thickness of 20 nm. The electron transport layer 84 is comprised by Alq which is 20 nm in film thickness, for example.

The light emitting layer 82 is composed of any one of a red light emitting layer 82R, a green light emitting layer 82G, and a blue light emitting layer 82B for each pixel. The red emitter layer 82R is made of Alq doped with DCM 1% having a film thickness of 30 nm, for example. The green light emitting layer 82G is made of TYG-201 having a thickness of 30 nm, for example. The blue light emitting layer 82B is made of, for example, a CBP doped with BAlq having a thickness of 20 nm of 5%, and a laminated film having a BCP having a thickness of 10 nm, for example.

On the light emitting layer 76, the back electrode 86 which consists of transparent electrode materials, such as ITO, and translucent electrode materials, such as Li, Mg, Al, is formed. The back electrode 86 is comprised by the laminated | multilayer film of the MgAg film | membrane with a film thickness of 15 nm, for example, and the ITO film | membrane with a film thickness of 150 nm, for example. In addition, the back electrode 86 is an electrode common to each pixel part.

On the transparent substrate 72 in which the transparent electrode 74, the light emitting layer 76, and the back electrode 86 were formed, the sealing plate 88 which consists of glass is formed, for example. The sealing plate 88 is for protecting the light emitting layer 76 made of an organic EL material from external air such as oxygen or hydrogen. Between the transparent substrate 72 and the sealing plate 88, the transparent substrate 72 and the sealing plate 88 are bonded and sealed with the epoxy resin adhesive 90 etc. in nitrogen atmosphere, for example. In addition, at this time, the getter agent which collects water is put between the transparent substrate 12 and the sealing plate 88, and the protection from external air is ensured. In other words, a transparent liquid getter agent is preferable.

Next, the driving method of the display device according to the present embodiment will be described in detail.

As a driving method of the display device which concerns on this embodiment, the two methods shown below can be considered, for example.

(Drive method 1)

In this driving method, the corresponding pixels of the organic EL display 10, the liquid crystal display 40, and the organic EL display 70 are driven simultaneously. In the organic EL display 10, 70, the color display part except the black part of a display image is displayed. On the other hand, the liquid crystal display 40 displays only the black part of a display image.

By using this driving method, the display device according to the present embodiment becomes a full-color double-sided light emitting display device. In the display device according to the present embodiment, since the organic EL display 10 is disposed on one display surface side and the organic EL display 70 is disposed on the other display surface side, luminance equivalent to both display surfaces can be obtained. Can be. However, similarly to the case of the driving method 1 in the display device according to the first embodiment, the image displayed on one display surface and the image displayed on the other display surface are symmetrical.

(Drive method 2)

In the present driving method, the color display portions other than the black portions of the display image are displayed on the organic EL displays 10 and 70. In the liquid crystal display 40, the whole image area | region is made into black display on one surface. In this driving method, the display of the liquid crystal display 40 need not be performed simultaneously with the driving of the organic EL displays 10 and 70.

By using this driving method, a full color image is displayed on the organic EL display 10 side display surface and the organic EL display 70 side display surface, respectively.

Moreover, when the liquid crystal display 40 is black display in the whole display image area like the present driving method, the effect of completely separating the image displayed on the organic EL display 10 and the image displayed on the organic EL display 70 There is also.

Therefore, the image displayed on the organic EL display 10 and the image displayed on the organic EL display 70 need not necessarily be corresponding images. For example, the image displayed on the organic EL display 10 and the image displayed on the organic EL display 70 may be the same, may be symmetrical, or may be completely different images. Alternatively, if either one of the organic EL display 10 or the organic EL display 70 is not driven, driving equivalent to the driving method 2 of the display device according to the first embodiment may be performed.

As a result of manufacturing the display device according to the present embodiment and performing an operation test, it was possible to perform full-color display that was transparent during normal operation (when the power was turned off) and had good contrast during image display. Moreover, when the said drive method 1 was used, the image was confirmed on both display surfaces. Moreover, when the said drive method 2 was used, different images could be displayed on the organic electroluminescent display 10, 70, respectively, and the contrast image was able to be displayed favorably on both surfaces.

As described above, according to the present embodiment, since the display device is configured by combining the self-luminous transparent display element and the transparent display element capable of black display, a good black display can be obtained even when the external light is strong, and the contrast is good in full color display. Can be carried out.

In addition, since the self-luminous transparent display elements are provided on both display surfaces, different information can be displayed on the back and the front of the display device. In addition, it is possible to prevent the display information from being reversed left and right at the back and the front of the display device.

Fourth Embodiment

A display device and a driving method thereof according to a fourth embodiment of the present invention will be described with reference to FIGS. 6 and 7. In addition, the same code | symbol is attached | subjected to the display apparatus which concerns on the 1st-3rd embodiment shown to FIGS. 1-5, and the component which is the same, and the description is abbreviate | omitted or simplified.

6 is a schematic cross-sectional view showing the structure of the display device according to the present embodiment, and FIG. 7 is a view for explaining the operation of the electrophoretic display 100.

In the display device according to the first to third embodiments, a transparent liquid crystal display is used as a transparent display element capable of black display, but other transparent display elements may be applied instead of the transparent liquid crystal display.

In the display device according to the present embodiment, as shown in FIG. 6, the electrophoretic display 100 is formed in place of the liquid crystal display 40 of the display device according to the first embodiment. In addition, electrophoretic displays are described, for example, in Japanese Patent Laid-Open No. 2003-161966.

The electrophoretic display 100 is formed on a transparent substrate 102 made of glass, quartz, resin, or the like. On the transparent substrate 102, the transparent electrode 104 which consists of an ITO film, for example, and the transparent insulating layer 106 which consists of a silicon nitride film are formed, for example. On the transparent insulating layer 106, for example, an electrode 108 made of aluminum is formed. On the transparent insulating layer 106 on which the electrode 108 is formed, the transparent substrate 112 is adhered through the partition wall and spacer 110. Between the transparent insulating layer 106 and the transparent substrate 112, the liquid 114 (for example, silicone oil) which has insulation and transparency is sealed. In this liquid, for example, an appropriate amount of positively charged particles 116 that are positively charged are dispersed.

Next, the operation of the electrophoretic display 100 will be described with reference to FIG. 7.

When a negative charge is applied to the transparent electrode 104 with respect to the electrode 108, the electrophoretic particles 116 are attracted to the transparent electrode 104, so that the liquid 114 is disposed on the transparent electrode 104. It moves up on the transparent insulating layer 106. As a result, the pixel portion is completely embedded by the electrophoretic particles 116, resulting in black display (FIG. 7A).

On the other hand, when negative charge is applied to the transparent electrode 104 to the electrode 108, the electrophoretic particles 114 are attracted to the electrode 108, and the liquid 114 is moved to the vicinity of the partition and spacer 110. Move. As a result, the electrophoretic particles 116 do not exist in the pixel portion and become transparent (FIG. 7B).

Therefore, the electrophoretic display 100 as shown in FIG. 6 also has a transparent display and a black display similarly to the liquid crystal display 40, and the display device according to the present embodiment is also the display according to the first embodiment. It can be driven in the same manner as the driving method of the device.

Thus, according to this embodiment, even if an electrophoretic display is used as a transparent display element which can display black, the display apparatus which can display the full color with favorable contrast, even if external light is strong can be comprised.

[Fifth Embodiment]

The display device and driving method thereof according to the fifth embodiment of the present invention will be described with reference to FIG. 8. In addition, the same code | symbol is attached | subjected to the display apparatus which concerns on the 1st-3rd embodiment shown to FIGS. 1-5, and the component which is the same, and the description is abbreviate | omitted or simplified.

8 is a schematic cross-sectional view showing the structure of the display device according to the present embodiment.

In the display device according to the first to third embodiments, a transparent liquid crystal display is used as a transparent display element capable of black display, but other transparent display elements may be applied instead of the transparent liquid crystal display.

In the display device according to the present embodiment, as shown in FIG. 8, an electrochromic light control glass 120 is formed in place of the liquid crystal display 40 that is the display device according to the first embodiment. In addition, the electrochromic dimming glass is described in Unexamined-Japanese-Patent No. 2002-268096, for example.

The electrochromic dimming glass 120 has a pair of transparent substrates 122 and 124 made of glass, quartz, resin, or the like. On the opposing surfaces of the transparent substrates 122 and 124, for example, transparent electrodes 126 and 128 made of an ITO film are formed, respectively. The electrolyte layer 130 and the electrochromic layer 132 are sandwiched between the transparent substrates 126 and 128.

Electrochromic layer 132 is composed of V ₂ O ₅ , Nb ₂ O ₅ , TiO ₂ , WO ₃ The reduction-type color-developing material _{and, NiO, Cr 2 O 3,} MnO 2, and oxidation color development-type material, such as CoO, such as be used. As the electrolyte layer 130, a composition in which a supporting electrolyte is mixed and dissolved in a polar solvent is usually used.

For example, in the case where a reducing color-emitting material is used for the electrochromic layer 132, when the transparent electrode 126 applies a voltage such that the positive electrode and the transparent electrode 128 become the negative electrode, the electrochromic dimming glass 120 Becomes transparent. In contrast, when the transparent electrode 126 applies a voltage such that the negative electrode and the transparent electrode 128 become the positive electrode, the electrochromic light-adjusting glass 120 becomes opaque (black).

Therefore, the electrochromic dimming glass 120 as shown in FIG. 8 can also be transparently displayed and black display similarly to the liquid crystal display 40, and the display device according to the present embodiment is also according to the first embodiment. It can be driven in the same manner as the driving method of the display device.

Thus, according to this embodiment, even if electrochromic dimming glass is used as a transparent display element which can display black, the display apparatus which can display the full color with favorable contrast, even if external light is strong can be comprised.

[Sixth Embodiment]

A display device and a driving method thereof according to a sixth embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the display apparatus which concerns on the 1st-3rd embodiment shown to FIGS. 1-5, and the component which is the same, and the description is abbreviate | omitted or simplified.

9 is a schematic cross-sectional view showing the structure of the display device according to the present embodiment.

In the display device according to the first to third embodiments, a transparent liquid crystal display is used as a transparent display element capable of black display, but other transparent display elements may be applied instead of the transparent liquid crystal display.

As shown in FIG. 9, the display device according to the present embodiment is provided with a gas chromatic dimming glass 140 instead of the liquid crystal display 40 of the display device according to the first embodiment. In addition, a gas chromatic dimming glass is described, for example in Unexamined-Japanese-Patent No. 2003-261356.

The gas chromatic dimming glass 140 is formed on the transparent substrate 142 made of glass, quartz, resin, or the like. On the transparent substrate 142, a magnesium thin film 144 having a thickness of 40 nm or less is formed. On the magnesium thin film 144, for example, a catalyst layer 146 made of palladium or platinum is formed. On the catalyst layer 146, a protective layer 148 made of a material which is permeable to hydrogen and impermeable to water, for example, a tantalum oxide thin film, a zirconium oxide thin film, or the like, is formed. The transparent substrate 152 is formed on the protective layer 148 through the gap 150. In addition, an atmosphere controller 154 for introducing hydrogen gas and oxygen gas is formed in the gap 150 so that the degree of hydrogenation and dehydrogenation can be adjusted.

In the case of the gas chromatic dimming glass, the gas introduced into the gap 150 by the atmosphere controller 154 is adjusted to hydrogenate the magnesium thin film 144 and becomes opaque (mirror) when dehydrogenated.

Therefore, the gas chromatic dimming glass 140 as shown in FIG. 9 also has a transparent display and a black display similarly to the liquid crystal display 40, and the display apparatus which concerns on this embodiment also by the 1st Embodiment It can be driven in the same manner as the driving method of the display device.

Thus, according to this embodiment, even when using a gas chromatic dimming glass as a transparent display element which can display black, the display apparatus which can display the full color with favorable contrast, even if external light is strong can be comprised.

Modified Embodiment

This invention is not limited to the said embodiment, A various deformation | transformation is possible.

For example, in the said 3rd Embodiment, although the sealing plates 28 and 88 were formed in the organic electroluminescent display 10 and 70, respectively, similarly to the case of the display apparatus which concerns on 2nd Embodiment, the liquid crystal display 40 Even if the sealing plate of the organic EL display 10 is used by the transparent substrate 42 of the () and / or the sealing plate of the organic EL display 70 by the transparent substrate 44 of the liquid crystal display 40 do.

Moreover, in the said 4th-6th embodiment, although the case where the other transparent display element which replaces the liquid crystal display 40 was applied to the display apparatus of 1st embodiment was shown, the same transparent display also in 2nd and 3rd embodiment The device can be applied.

Moreover, in the said embodiment, although the transparent organic electroluminescent display was used as a self-emitting transparent display element, other display elements can also be applied as a self-emitting transparent display element. For example, the display apparatus of this invention can also be comprised using an inorganic EL element.

Moreover, in the said embodiment, although the liquid crystal display, the electrophoretic display, the electrochromic dimming glass, and the gaschromic dimming glass were used as the transparent display element which can display black, the display which can control light transmission and opacity If so, other displays may be applied. Moreover, as a transparent display element which can display black, it is especially preferable that it is controllable only by an electric field (power consumption is almost 0).

Industrial availability

The display device and the driving method thereof according to the present invention realize good full color display of contrast that is hard to be affected by external environment such as external light, and protection of privacy and security of display information. Accordingly, the display device and the driving method thereof according to the present invention are very useful for applications to glass window televisions, glass window advertising display devices, transparent televisions, transparent advertising display devices, transparent PC monitors, displays for mobile phones, and the like.

Claims (16)

A self-luminous first display element which is in a light transmissive state when no image is displayed, A second display element formed on said first display element and capable of switching between a light transmission state and a light transmission state; A display device characterized by displaying a predetermined image by superimposing an image displayed by the first display element and an image displayed by the second display element. The method of claim 1, The first display element puts the black display portion of the predetermined image in a light transmissive state, And the second display element makes the black display portion of the predetermined image light-transmissive. The method of claim 1, The first display element puts the black display portion of the predetermined image in a light transmissive state, And the second display element is in an optically transmissive state. The method of claim 1, It is provided on the said 2nd display element, Comprising: It further has a self-luminous 3rd display element which is a light transmissive state, when an image is not displayed, A first predetermined image is displayed by superimposing an image displayed by the first display element and an image displayed by the second display element, A display device characterized by displaying a second predetermined image by superimposing an image displayed by the third display element and an image displayed by the second display element. The method of claim 4, wherein The first display element sets the black display portion of the first predetermined image to a light transmissive state, The third display element puts the black display portion of the second predetermined image in a light transmissive state, And said second display element makes the black display portions of said first predetermined image and said second predetermined image in a light-transmissive state. The method of claim 4, wherein The first display element sets the black display portion of the first predetermined image to a light transmissive state, The third display element puts the black display portion of the second predetermined image in a light transmissive state, And the second display element is in an optically transmissive state. The method according to any one of claims 1 to 6, One transparent substrate used for a said 1st display element is common with one transparent substrate among a pair of transparent substrate which a said 2nd display element has. The method according to any one of claims 4 to 6, One transparent substrate used for the first display element is common with one of the pair of transparent substrates included in the second display element, One transparent substrate used for the third display element is common with the other transparent substrate among the pair of transparent substrates of the second display element. The method according to any one of claims 1 to 8, And the first and third display elements are display elements using an electroluminescent element. The method according to any one of claims 1 to 9, And the second display element is a liquid crystal display, an electrophoretic display, an electrochromic dimming glass, or a gaschromic dimming glass. A display device having a self-luminous first display element in a light transmissive state when not displaying an image, and a second display element formed on the first display element and capable of switching between a light transmissive state and a light impermeable state. As a driving method, A predetermined image is displayed by superimposing an image displayed by the first display element and an image displayed by the second display element. The method of claim 11, The black display portion of the predetermined image is made into the light transmissive state by the first display element, and the black display portion of the predetermined image is in the light transmissive state by the second display element, thereby making the predetermined image And a display method for driving the display device. The method of claim 11, The predetermined image is displayed by causing the black display portion of the predetermined image to be in a light transmissive state by the first display element and the entire display area to be in an optically transmissive state by the second display element. Method of driving the display device. A self-luminous first display element in a light transmissive state when not displaying an image, a second display element formed on the first display element and capable of switching a light transmissive state and a light impermeable state, and the second A driving method of a display device which is formed on a display element and has a self-luminous third display element which is in a light transmissive state when no image is displayed, The first predetermined image is displayed by superimposing the image displayed by the first display element and the image displayed by the second display element, A second predetermined image is displayed by superimposing an image displayed by the third display element and an image displayed by the second display element. The method of claim 14, The first predetermined image is displayed by setting the black display portion of the first predetermined image by the first display element in the light transmissive state and the entire display area by the second display element in the light transmissive state. , The second predetermined image is displayed by setting the black display portion of the second predetermined image to the light transmissive state by the third display element and the entire display area to the light transmissive state by the second display element. Method of driving a display device, characterized in that. The method of claim 14, The black display portion of the first predetermined image is made into a light transmissive state by the first display element, and the black display portion of the first predetermined image is made into a light transmissive state by the second display element. Display a first predetermined image, The black display portion of the second predetermined image is made into a light transmissive state by the third display element, and the black display portion of the second predetermined image is made into a light transmissive state by the second display element. And a second predetermined image is displayed.

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